1. Field of the Invention
The present invention relates to a thin film transistor array panel.
2. Description of Related Art
An active type display device such as a liquid crystal display (LCD) and an organic light emitting diode (OLED) display includes a plurality of pixels arranged in a matrix and including field generating electrodes and switching elements. The switching elements include thin film transistors (TFTs) having three terminals, gate, source, and drain. The TFT of each pixel selectively transmits data signals to a field-generating electrode in response to gate signals.
The display device further includes a plurality of signal lines for transmitting signals to the switching elements, which includes gate lines transmitting gate signals and data lines transmitting data signals.
The LCD and the OLED include a panel provided with TFTs, field-generating electrodes, and signal lines, which is referred to as a TFT array panel.
The TFT array panel has a layered structure that includes several conductive layers and insulating layers. Gate lines, data lines, and field-generating electrodes are formed of different conductive layers and separated by insulating layers.
When an active area on a backplane for LCDs is too large to use an exposure mask, the entire exposure is accomplished by repeating a divisional exposure called step-and-repeat process. One divisional exposure unit or area is called a shot. Since transition, rotation, and distortion are generated during light exposure, the shots are not aligned accurately. Accordingly, parasitic capacitances generated between signal lines and pixel electrodes differ depending on the shots, and this causes the luminance difference between the shots, which is recognized at the pixels located at a boundary between the shots. Therefore, the stitch defect is generated on the screen of the LCD due to luminance discontinuity between the shots. In addition, the difference in the parasitic capacitance causes the difference in the kickback voltage to yield flickering.